Tilt the phone and every tile slides to the low wall. Line up three of a colour to clear them;
a tilt mid-cascade can set off the next clear. Swipe a tile to swap it with a neighbour.
New tiles pour in from the high side, so keep clearing before the board fills.
Hold the phone the way you want to play when you press Start: that pose is level. Without tilt, use the arrows or the arrow keys.